EP 0578833 A4 19940629 - VARIABLE FOCUS VISUAL POWER CORRECTION APPARATUS
Title (en)
VARIABLE FOCUS VISUAL POWER CORRECTION APPARATUS
Publication
Application
Priority
JP 1771592 A 19920203
Abstract (en)
[origin: WO9315432A1] This invention aims at reducing astigmatism, securing uniform refraction power, preventing irregular reflection due to existence of a plurality of refraction planes, and reducing the size of a lens system in a variable focus type visual power correction apparatus in which a plurality of optical lenses are superposed in such a manner that main meridians thereof are coincident with one another, and refraction power of which changes upon relative sliding motion in the direction of the plane of superposition along the meridians. The magnitude of astigmatism of the lens as a single substance constituting the variable focus type visual power correction apparatus is set so that when the magnitude is expressed by contour lines having an arbitrary dioptry gap, each contour line is substantially parallel to the meridian and describes a straight line, and the magnitude of refraction power is substantially rectangular to the meridian and describes a straight line. This structure can eliminate astigmatism, the refraction power in the region where the eyeglass lenses superpose with one another becomes constant and an eyeglass lens having optical performance equivalent to that of a mono-focal lens can be obtained.
IPC 1-7
IPC 8 full level
CPC (source: EP)
G02C 7/061 (2013.01); G02C 7/065 (2013.01); G02C 7/081 (2013.01); G02C 2202/16 (2013.01)
Citation (search report)
- [A] FR 2444955 A1 19800718 - LE I TOCHNOI [SU]
- [A] US 4403840 A 19830913 - OKUN MILTON R [US]
- [A] US 3598479 A 19710810 - WRIGHT BASIL MARTIN
- [A] US 4300818 A 19811117 - SCHACHAR RONALD A
- [A] US 4645317 A 19870224 - FRIEDER PHILIP M [US], et al
- See references of WO 9315432A1
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
WO 9315432 A1 19930805; EP 0578833 A1 19940119; EP 0578833 A4 19940629
DOCDB simple family (application)
JP 9300121 W 19930202; EP 93902557 A 19930202